Asylum: According to Black’s Law dictionary, this term means shelter; refuge; protection from the hand of justice. The word includes not only place, but also shelter, security, protection; and a fugitive from justice, who has committed a crime in a foreign country, "seeks an asylum.”
Immigrant: According to Black’s Law dictionary, this term describes a person who enters a country for permanent residence from another country.
Internally Displaced Persons (IDP): According to the UNHCR, internally displaced persons, or IDPs, are among the world’s most vulnerable people. Unlike refugees, IDPs have not crossed an international border to find sanctuary but have remained inside their home countries. Even if they have fled for similar reasons as refugees (armed conflict, generalized violence, human rights violations), IDPs legally remain under the protection of their own government – even though that government might be the cause of their flight. As citizens, they retain all of their rights and protection under both human rights and international humanitarian law.
Non-refoulement: Non-refoulement is a principle of international law which forbids the rendering of a true victim of persecution to his or her persecutor.
Refugee: Pursuant to the 1951 Convention, the term refugee” shall apply to any person who has well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, and is outside the country of his nationality and is unable or, owing to such fear, is unwilling to avail himself of the protection of that country; or who, not having a nationality and being outside the country of his former habitual residence as a result of such events, is unable or, owing to such fear, is unwilling to return to it.
Repatriation: Pursuant to Black’s Law dictionary, repatriation takes place when a person who has been expatriated regains his nationality (expatriate is when a citizen of country A living in country B. Classification of this citizen occurs regardless if the citizen has a short stay or an extended or lifetime stay in country B).